A rotary switch mechanism is usually installed in for example a computer peripheral device to generate a control signal. In response to the control signal, a specified function (e.g. a sound volume adjusting function) may be executed.
FIG. 1 is a schematic exploded view illustrating a conventional rotary switch mechanism. The conventional rotary switch mechanism is disclosed in for example U.S. Pat. No. 7,750,256. As shown in FIG. 1, the conventional rotary switch mechanism 1 comprises a dial assembly 12, a push button 13, a rotary switch 14, an elastic element 15, five dome switches 161˜165 and a circuit board 17.
The dial assembly 12 comprises plural projecting parts 121. The push button 13 comprises a central button part 131 and a ring-shaped part 132. The ring-shaped part 132 is connected with the central button part 131 and surrounds the central button 131. The ring-shaped part 132 comprises a mounting tab 133 to be fixed in a corresponding mounting aperture 171 of the circuit board 17.
Upon rotation of the dial assembly 12, the plural projecting parts 121 interact with the handle 141 of the rotary switch 14. Consequently, the handle 141 is rotated in either the clockwise direction or the anti-clockwise direction, and different rotating signals are generated to control a specified function. Moreover, due to a restoring force resulted from the elastic element 15, the rotation of the dial assembly 12 results in a multi-step rotating feel. Moreover, by pressing the central button part 131, the dome switch 161 is triggered to generate a pressing signal. In response to the pressing signal, another function is controlled. Moreover, by pressing the surface of the dial assembly 12 to have the central button part 131 trigger the dome switches 162˜165, two other functions may be controlled.
From the above discussion, the conventional rotary switch mechanism 1 may be operated to control at least four kinds of functions. For example, a playlist is selected by rotating the dial assembly 12; the sound volume is adjusted by pressing the dome switches 163 and 165; the next/previous song switching function is controlled by pressing the dome switches 162 and 164; and the playback of a song is started or paused by pressing the push button 13.
Although the conventional rotary switch mechanism 1 may be operated to control four kinds of functions, these four functions sometimes fail to meet the user's requirements because the electronic device is gradually developed to have a variety of functions. Moreover, the conventional rotary switch mechanism 1 uses many dome switches to control some specified functions. If some specified functions, for example the functions of zooming in/out an image or rotating the image, are controlled by pressing the dome switches, the pressing gestures of controlling these functions usually fail to be directly perceived through the senses of the user. Moreover, since the dial assembly 12 is in direct contact with the push button 13, the dial assembly 12 and the push button 13 usually nib against each other during rotation of the dial assembly 12. If the conventional rotary switch mechanism 1 has been long used, the abrasion between the dial assembly 12 and the push button 13 may shorten the use life of the rotary switch mechanism 1. Moreover, if the force exerted on the dial assembly 12 is not uniformly distributed, the dial assembly 12 is readily inclined toward a side to erroneously trigger the dome switches 162˜165. Under this circumstance, the dial assembly 12 is erroneously operated.
Therefore, there is a need of providing an improved rotary switch mechanism so as to obviate the drawbacks encountered from the prior art.